1. Field of the Invention
The invention generally relates to safety equipment. More specifically, this invention relates to an improved fall protection harness with controlled descent, said harness having an integral Reserve Suspension Relief Strap (RSRS). It is especially suited for hunters to wear while in a tree stand. With the extended range of the latest improvements, this invention may be worn by many industrial workers, including wind turbine blade repair personnel who perform services about 200 feet or more above ground level.
2. Background
As reported by Richard Holdcraft in his 2004 article entitled “Safety Harnesses: Self-Recovery/Self-Rescue”, a then recent Consumer Product Safety Commission (CPSC) report estimated that 6,410 injuries attributed to tree stand use were treated in U.S. hospitals nationwide in 2001. That was based on a review of their National Electronic Injury Surveillance System (NEISS). Their data sources further indicated that there were 137 incidents involving tree stands from 1980 through 2001. Included in these statistics were 62 deaths, 55 injuries, 17 incidents not involving death or injury, and 3 incidents in which the outcome is unknown. Of the 137 incidents, 54 mentioned tree stand failures resulting in 6 of the deaths, 40 injuries, and 8 incidents without injury. There were eight incidents involving hanging or traumatic asphyxiation by a safety belt around the waist or chest that resulted in death. These are only the incidents reported by hospitals; they do not include statistics for incidents that are misclassified but still tree stand related.
The CPSC estimates there may be at least 11 million tree stands in use by hunters. The estimated annual shipments of all manufactured tree stand types could exceed 1.4 million units. The total annual retail sales of all manufactured tree stand types range from $75 million to $150 million. The use of tree stands for hunting has increased dramatically in the past few years. Along with the increase in their use comes an increase in the number of serious or fatal injuries. While firearms related incidents has declined tremendously since mandatory hunter education courses were instituted and blaze orange laws were passed, the number of tree stand related incidents has increased significantly. During 2003, North Carolina Wildlife Resources Commission reported that 75% of their hunting fatalities were due to tree stand accidents.
Tree stands are used by hunters who prefer to hunt from elevated positions to increase their field of view and to decrease the likelihood of detection by game animals on the ground. A tree stand is basically a seat and footrest unit that is either strapped to a tree or its branches, or is part of a free-standing tower design. Several styles of tree stands are available, such as an integral ladder and platform stand, fixed-position stands; and self-climbing stands. Unique features distinguish each style.
Hunters have a variety of features to choose from when selecting tree stands. Key features include portability, bars, chains, straps and rails that affix the seating device to the tree, gun rests, bow rests, outward facing stands, forward facing stands, and multiple-occupancy stands that include a tree stand with a seating capacity for four individuals.
A non-statistical survey conducted by Deer and Deer Hunting magazine in 1993 and again in 1999, concluded that the most common reason for falls from elevated hunting positions was due to some type of structural failure. These types of failures included rotted wood, loose nails, nails pulled through boards, broken bands, bolts, ropes, or other attaching devices. There were no statistics presented regarding failures of commercially manufactured tree stands.
Hunters are encouraged through informational and educational campaigns to use fall protection devices to prevent death and serious injuries from falls while hunting from tree stands. A fall protection device is comprised of various components such as straps, belts, buckles and other hardware configured for the purpose of arresting a fall from an elevated position.
Fall protection devices are also referred to as fall restraint systems or fall arrest systems. Fall protection devices work as a system because each component of the device is dependent on other components for operational integrity. The term arrest and restraint can carry nuances of meaning. Instructions provided by one tree stand manufacturer have a warning that states that a full-body harness that is included with the purchase of the tree stand is not intended to arrest a fall, but is intended to restrain a fall. For purposes of this article, a fall protection device is used as an inclusive term for the various types of straps and harnesses worn by hunters to arrest, or stop, a fall. Furthermore, the purpose of a fall protection device is understood to be the stoppage of a fall, not the prevention of a fall.
A safety belt is a single strap or rope, worn either around the waist or chest, with a lanyard that secures the device to an anchor on the tree. The safety belt is sometimes described as a waist belt, chest belt, body belt, safety strap, single strap, or fall arrest belt. While a number of manufacturers include full-body harnesses with the purchase of their tree stands, a few may still provide safety belts with their stands. Safety belts can be purchased separately as an accessory item. Safety belts are among the simplest and least expensive of fall protection devices sold to hunters. Hunters are subject to serious injury using a device around the waist or chest and can become inverted. They can lose consciousness in less than 2-3 minutes. When hunters fall with a belt around the waist or chest, self-recovery or self-rescue may become impossible. In January 1998, the Occupational Safety and Health Administration (OSHA) prohibited the use of safety belts as a personal fall arrest system. The decision to prohibit safety belts around the waist was based on extensive studies showing the hazardous effects of the initial fall impact forces and the pressure exerted on the body by these restraints.
A chest and shoulder harness is basically a safety belt with shoulder straps. Instead of being worn around the waist, it rides across the chest and under the arms. If the hunter lifts their arms above their heads during self-recovery/self-rescue, they are subject to sliding out of the harness. During a fall, static loads in excess of several thousand pounds are placed against the chest which could cause ribs to break and penetrate the lungs or heart causing a fatality. The potential for asphyxiation associated with safety belts, straps, or ropes around the waist or chest is the greatest hazard to hunters.
A full-body or parachute style safety harness includes straps for the pelvic and thigh areas in addition to the shoulder straps. A full-body harness fastens around the hunter in a manner designed to contain the torso and distribute fall arrest forces over the upper thighs, pelvis, chest and shoulders, with means for attaching it to other components or subsystems. It is often referred to as a safety harness, or four-point safety harness. Typically, they include a harness, lanyard, anchorage means and connecting hardware. When properly adjusted and worn, it is nearly impossible for the hunter to be ejected from same. Full-body harnesses are generally more expensive, however.
Many individuals hunt alone in secluded areas and would most likely have to rescue themselves if suspended by a fall restraint system. Recently developed guidelines recommend that hunters immediately attempt a self-recovery or self-rescue when suspended after a fall arrest. Step-by-step procedures for self-rescue are usually included in instructions provided by tree stand and fall restraint systems manufacturers. A video produced by the National Bowhunter Education Foundation and the Treestand Manufacturers Association included with some manufacturer's tree stands suggests that hunters carry a knife to cut themselves out of a harness when suspended after a fall. They also state that once the hunter's body weight is off the harness, he/she should “bear hug” the tree and carefully climb down. That maneuver requires considerable physical coordination and strength, however. Additionally, hunters may not be able to react quickly enough to perform a self-recovery or self-rescue maneuver, as in the instance of a tree stand collapse where no handholds are available.
Advising hunters to cut themselves out of a harness may not adequately address another issue of post-fall rescue. Cutting or loosening the straps or otherwise trying to slip out of the fall restraint system is illogical as it introduces another serious hazard. Such straps can slip up the torso and incapacitate the hunter by pinning their arms against the body or cause asphyxiation by exerting pressure on the hunter's chest or neck. In a panic, the hunter could even loosen the straps completely and fall from the harness to the ground.
Some hunters elect to attach a long, ¾ to 1 inch thick line from their hunting height to the ground using a Prussic knot. The Prussic knot is attached to that line so as to allow sliding along its length. A full-body harness then attaches to the long line with a tether or anchor line. When pressure is applied to the knot during a fall, it grips the line and holds the hunter in place. This is a redundant system yet it gives the hunter another option for self-recovery or self-rescue.
Regardless of which type of safety harness the hunter uses while hunting from a tree stand, they should be aware of a condition medical practitioners describe as orthostatic intolerance. Orthostatic intolerance may be defined as “the development of symptoms such as light-headedness, palpitations, tremulousness, poor concentration, fatigue, nausea, dizziness, headache, sweating, weakness and occasionally fainting during upright standing”. While in a sedentary position, blood can accumulate in the veins which are commonly called “venous pooling,” and cause orthostatic intolerance.
An accumulation of blood in the legs reduces the amount of blood in circulation. The body reacts to this reduction by speeding up the heart rate in order to maintain sufficient blood flow to the brain. If blood supply is significantly reduced, that reaction will not be effective. The body will abruptly slow the heart rate and blood pressure in the arteries will diminish. During severe venous pooling, the reduction in quantity and/or quality (oxygen content) of blood flowing to the brain causes fainting. This reduction also can have an effect on other vital organs such as the kidneys. The kidneys are quite sensitive to blood oxygen. Renal failure can occur with excessive venous pooling. And if these conditions persist, very serious repercussions may develop.
Orthostatic intolerance may still be experienced by hunters using certain fall arrest systems. Following a fall, the hunter may remain suspended in a harness. Sustained immobility may lead to unconsciousness. Depending on the length of time a suspended hunter is unconscious and immobile, and the level of venous pooling, the resulting orthostatic intolerance may lead to serious consequences. While not common, such incidents are often referred to as “harness-induced pathology” or “suspension trauma.”
Prolonged suspension in fall arrest systems can cause orthostatic intolerance, which, in turn, leads to serious physical injury. Research indicates that suspension in a fall arrest device can result in more serious consequences in less than 30 minutes. To reduce the risk associated with prolonged suspension, hunters should initiate self-recovery/self-rescue as soon as possible after a fall arrest.
All tree stand safety courses should train hunters to use fall arrest systems and other personal protective equipment correctly. Hunters, who wear fall arrest devices while hunting, and those who may perform rescue activities, should also be trained in: (i) how to ascertain whether their harness is properly fitted and worn, so that it performs as intended; (ii) how orthostatic intolerance/suspension trauma may occur; (iii) the factors that may increase a hunter's risk; (iv) how to recognize the signs and symptoms identified above; and (v) the appropriate rescue procedures and methods to diminish risk while suspended.
The use of belts, straps or ropes around the waist or chest alone is not preferred. A full-body safety harness reduces the likelihood of serious, traumatic injury to hunters. In the not so distant future, devices that just wrap around the hunter's waist or chest may be prohibited with full-body safety harnesses being the only type permitted to save lives.
Safety harness use by hunters has experienced a sharp rise in recent years with the rise in popularity of climbing-type tree-stands. Approximately 90% of deer hunters have hunted from an elevated stand at one time or another. One of the most popular types of stands attaches by a cantilever to the trunk of a tree. It lets its user ascend the tree, often to heights of 35 feet, by alternately moving upper and lower sections of the stand in a sit-and-stand, “ratchet-type” action. Such climbing tree stands depend on their cantilever design to impinge on and grip the tree trunk. Unfortunately, such stands have been prone to sudden and unexpected slippage or upset causing them to fall rapidly down the tree or abruptly shift positions and often causing the stand occupant to lose his or her balance and fall to the ground.
At other times, hunters fall out of their stands after falling asleep, during the climbing operation, or when stepping from a fixed ladder onto the platform of another stand type known as a “lock-on” tree stand. Many hunters who use elevated tree stands, will experience a fall at one time or another. And a large number of those who fall sustain serious, often catastrophic injuries, including broken bones, ruptured spleens, internal bleeding, severed arteries, paralysis from spinal injuries, even death.
The use of a safety harness to arrest one's fall from an elevated position is well known. Fall-arresting harnesses are commonly used and even mandated by law in certain commercial and industrial applications, especially for individuals working at elevated heights like ironworkers, arborists, window washers, sign installers, roofers, and others. In recreational sports, including deer hunting, full-body safety harnesses, as well as chest-harnesses, and safety waist-belts, are used as fall-arresting protective devices. However, traditional harnesses lack any provision for the wearer who experiences a fall to gradually and safely descend to the ground or other level of safety. Once suspended by a safety harness, only the most athletic and fit of hunters would have an ability to re-enter their tree stand, or “hug the tree” and shimmy down its trunk. That procedure requires the victim to cut the tether from which he/she is suspended, an incredibly dangerous action that can lead to serious injury or death. Remaining suspended from the tree in a safety harness offers no better long-term survival prospects for the victim, however, due to the considerable danger and risk from suspension trauma that is likely to occur very quickly after a fall.
In the case of belt harnesses, it is not uncommon for asphyxiation to occur less than one hour after becoming suspended. With chest harnesses, the survival time can be a bit longer. While full-body safety harnesses were thought to be safer than belt or chest varieties, the constriction of blood flow to one's lower extremities as a result of suspension in such a harness can lead to serious injury or even death in an amazingly short period of time, in some cases as little as 15 to 30 minutes. Even if a hunter is fortunate enough to be discovered by rescuers in a short period after falling and has not succumbed to the effects of suspension trauma, the danger to both victim and rescuers in getting that individual back down to the ground presents a daunting challenge.
If a person falls in a remote location and finds himself suspended in a harness with no controlled descent capability, the impact of a fall may be prevented. But the victim may still be exposed to a critical, life-threatening emergency situation. Accordingly, there is need for a simple, reliable, yet lightweight and economical emergency descent system for a fall-arresting or other type safety harness. Such a system could be used by hunters, rock climbers, recreational tree climbers, as well as numerous industrial applications like billboard installers, steel erectors, tower constructors, maintenance personnel, roofers, arborists, and the like. Such a system could further provide controlled descent in the event one needs to escape under emergency circumstances from an elevated building location, the upper floor of a multi-story home or office.
Relevant publications to the present invention include the rescue apparatus of Henson U.S. Pat. No. 6,820,721, assigned to American Escape Systems, Inc. Therein, a device with a stand alone “descender” was mounted on the chest portion of a harness. A preferred embodiment included a camshaft in the descender for accommodating body weight differences of the wearer.
Brda U.S. Pat. No. 4,580,658 showed a device for lowering individuals on a rope. With a friction cylinder, this device arrests further movement along the rope. A control lever (element 19) is situated within reach of the wearer.
Bell U.S. Pat. No. 5,878,833 disclosed a fall prevention and lowering system in which the lowering device, element 300, could be stored in a compartment on the harness until needed.
Another series of references show clamps for rope lowering apparatus. Bowker U.S. Pat. No. 4,678,059, for example, replaced a Figure 8-shaped device with one having an oval ring that fits over a three-sectioned clasp for mountain climbing. In Steffen U.S. Pat. No. 4,311,218, its ladder-like concept was described as a braking device with a first embodiment having four crossbars (element 26) with three braking bars (element 32) situated there between. An alternate element (FIG. 8) used a fourth braking bar.
A rappel tool was the subject of Sadeck U.S. Pat. No. 6,095,282, assigned to the U.S. Army. Alternate ways for weaving rope through and about that device were shown in its FIGS. 3 through 7. A similar friction wrap was shown for top ladder 116 per FIG. 9 of Ostrobrod U.S. Pat. No. 6,962,238.
Numerous other safety harnesses patent protect their material selection, relative weight and/or other advantages over the art. In both Fisk et al. U.S. Pat. No. 5,203,829 and Zeissler et al. U.S. Pat. No. 6,874,596, devices with front D-rings were shown.
Finally, a pending U.S. Application by Harris published Jun. 1, 2006 as No. 2006/113147, showed a combined fall arrest harness with controlled descent through a friction release mechanism in a shoulder strap of that harness. That combination employed rope, line or webbing in a backpack addition to the rear of said harness. Various embodiments included encasing the webbing/rope in a hard, metallic box or other heavy, bulky or awkward external connector. Unfortunately, with the manner in which webbing or rope is wrapped by Harris, the wearer may not necessarily survive a head first fall. The means for configuring line in its backpack makes the Harris device more prone to internal tangling and/or improper fall stoppage.